Extremum seeking methods for optimization of variable cam timing engine operation

Automotive engines have been increasingly equipped with devices that can vary engine parameters with operating conditions. Optimizing these parameters via standard engine mapping and calibration has become a very time consuming task. The specific problem under consideration in this paper is optimization of intake, exhaust, and spark timings to improve the brake specific fuel consumption of a dual-independent variable cam timing engine. We have explored extremum seeking (ES) as a method to find the optimal setting of the parameters. During ES, the engine is running at fixed speed and torque in a dynamometer test cell, while an optimization algorithm is iteratively adjusting the three parameters. For our purposes, we have modified several algorithms available in the literature. The details about the algorithms and the experimental results they produced are presented and discussed in the paper.